THz reflection imaging for internal structure analysis of artworks

Terahertz (THz) spectroscopy and THz imaging techniques are expected to have great potential for the noninvasive analysis of works of art. THz waves can penetrate opaque materials and create three-dimensional maps of materials by spectroscopic imaging non-destructively. Satisfactory results using model samples have been obtained by many institutions. In particular, the imaging by using THz pulses in reflection mode make it possible to observe internal structure of works of art non-intensively. The structure reveals the technique which interests art historians as well as conservators. Moreover, detecting hidden defects, such as separation between painting and preparation layers of paintings, helps conservators to plan restoration process.